Archives for category: Molding and Casting

image from the film The Princess Bride

closeup from the movie

This is a prop I’ve wanted for a while. There’s been so-so reference material for a long time pieced together by other hopeful collectors. We’ve got some great close-ups and screen captures from the film itself. The goblet wasn’t created for the film, so there are a bunch of them out there in the world. They’re rare, but they exist. A member of posted some pictures recently of the one they happened to have already owned by chance. Another member posted pics they found from an eBay and Etsy auction they found while browsing Pintrest. Judging by their descriptions of the items, and a private message to one of them, none of the sellers knew they were used in the film.

Using these pictures as reference material, I’ve been able to sculpt a CAD model using AutoCAD and Meshmixer, and have printed out a goblet in plastic using the DittoPro at the Baltimore Node Makerspace. The final plan is to cast these goblets in lead-free pewter.

I first created a sketch of the model to get a good feel for it and to see if I ran into any trouble making the model. After creating a rough sketch, I got some feedback. We know the base is a bit bigger, 3.5″ instead of 3″ like I originally drew. The circles around the top are different sizes, 3 big and 3 small. The lower three ovals are way more squished than I had originally draw. I went back and recreated the goblet, making these changes.

Some times I run into a feature that’s too difficult for me to model in AutoCAD and I have to use a mesh modeling tool, like Meshmixer. This usually happens if it’s a very complex curve, or a variable radius fillet. Sometimes there’s also a feature that ends up being way easier to model in Meshmixer anyway, or something that is so simple to do in Meshmixer it’s not worth fiddling with it in AutoCAD. Since it’s very difficult to go backwards from Meshmixer back into AutoCAD, I want to be sure to save all of these Meshmixer tweaks for the end, and do as much as I can directly in AutoCAD first.

I was able to create the entire goblet in AutoCAD except for smoothing out a seam I created on the petals, and the complex curve where the fins blend into the neck of the goblet. The part where the fins curve into the goblet cup is easy, but where they start to smooth out near the bottom is hard so I just go over that area with a smoothing brush in Meshmixer.

Based on the seams seen on the screen-used prop, I can tell that it was originally cast from a rigid multi-piece plaster or rammed sand mold. We can see that there are seams down the sides of the goblet in three places. I personally don’t want to use plaster to cast the mold for this, and would prefer to create it from a split rubber mold for simplicity. It’s much easier for me to make the rubber mold than the multi-piece plaster mold, and much safer. I’ve read for plaster molds you have to make sure they’re completely dried out or else they’ll explode when you pour molten metal into them because the water expands so fast. I have experience with silicone rubber mold making but not plaster, and for this project I want to use the silicone. I do still want the seams to be in the part as if I cast it in a multi-piece mold, so I’m adding them to the CAD model. My hope is that the final cast piece will appear to still have come from a multi-piece mold instead of the split rubber one.

closeup shot showing top circles are different sizes

reference image from an etsy seller

reference image from an etsy seller

excellent reference shot
CAD model after making several adjustments
wireframe view of initial sketch

initial sketch model

I’ll be updating this blog post as I work on the project. Please check back soon to see my progress.

I’ve had these for a bit but I wanted to post this build thread. I also made the Schwartz ring from Spaceballs, but here’s a detailed build of the pendant than Lonestar wears in the film.  I started with the screen capped reference image.

I created the 3d model in AutoCAD.

I printed it in Black Detail and in the Frosted Ultra Detail material from Shapeways.

With the help of a professional caster, I had a silicon mold made, wax cast from the mold, and the wax is used in the lost wax casting process to produce it in antique bronze. The mold is seen there in blue.

I’ve then applied a patina using liver of sulfer, disolved in water.

Dipping the pieces in the solution for a couple minutes made them dark.

To neutralize the reaction, I then dipped them in a baking soda and water mixture.

and brushed it to bring out the details.